A208399 Smallest prime factor of (n^n)^2 + 1 having the form k*n+1.

17, 73, 65537, 41, 1297, 13564461457, 193, 6481, 1676321, 251857, 97, 380329, 1009, 33601, 59649589127497217, 137, 11019855601, 1217, 76001, 3697, 881, 428353, 193, 4001, 8737, 530713, 7841, 7830180737690995967783421720386927955722346842901104163321719186184830340945285361

Offset

2,1

Comments

The corresponding k are in A208400.

Links

Table of n, a(n) for n=2..29.

Example

a(3) = 73 because (3^3)^2 + 1 = 2*5*73 and the smallest prime divisor of the form k*n+1 is 73 = 24*3+1.

Mathematica

Table[p=First/@FactorInteger[(n^n)^2+1]; Select[p, Mod[#1, n] == 1 &, 1][[1]], {n, 2, 20}]

Crossrefs

Cf. A208400.

Sequence in context: A112013 A165691 A154419 * A097223 A296113 A231779

Adjacent sequences: A208396 A208397 A208398 * A208400 A208401 A208402

Keyword

nonn

Author

Michel Lagneau, Feb 27 2012

Status

approved